1. Field of the Invention
The present invention is generally directed to a process for preparing a siding material. More particularly, the present invention relates to a process for preparing cellular polyvinyl chloride materials for use as siding on buildings to mimic traditional, cedar wood clapboard siding.
2. Background of the Invention
Traditionally, siding, e.g., housing siding, is made from cedar wood, fiber cement, engineered wood, and vinyl. Each of these materials, however, has certain inherent problems when used as siding.
For example, siding made from cedar wood tends to absorb moisture, and to, consequently, warp, decay, and rot. Additionally, insects are attracted to the wood, and, therefore, contribute to the decay. Furthermore, when painted, the wood tends to blister, peel, and crack.
Although it absorbs less water than wood siding materials, fiber cement siding does absorb some moisture. Additionally, painted fiber cement siding suffers some of the same problems as does painted wood siding. To reduce the moisture and paint problems, the cut edges of the fiber cement siding must be carefully treated. Furthermore, fiber cement is unduly heavy, brittle, requires specialized tools and instruments for installation, and debris formed during its installation may create health risks. For these reasons, then, fiber cement siding is difficult to install.
With regards to engineered wood, all engineered wood includes wood flour. Accordingly, similar to the wood siding, wood flour absorbs water, swells, warps, decays, rots, attracts insects and sheds paint.
Vinyl siding is formed into 12 foot clapboards from thin sheets of rigid poly vinyl chloride (“PVC”). The use of vinyl siding improves upon the use of wood, in that vinyl does not warp or rot to the same degree as does wood. However, formed vinyl clapboards are very light and hollow giving them a flimsy look and feel. Additionally, vinyl siding must be overlapped to accommodate expansion and contraction. As a result, a tell-tale sign of vinyl versus wood siding is the overlapping joint that appears every 12 feet on all vinyl siding installations. Also, vinyl siding must be inserted into ‘j-channel’ installed around windows, doors and at all corners in order to accommodate expansion and contraction of the PVC with changes in temperature. Further, vinyl siding chalks over time; i.e. a white powder rises to the surface; especially on darker colors, thereby diminishing the appearance of the siding.
An improved product for use as siding is cellular PVC. Similar to rigid vinyl siding manufactured from PVC, cellular PVC siding expands and contracts about ¼ inch per 14 foot clapboard with changes in temperature of about 50 degrees Fahrenheit. The prior art has attempted to restrict such expansion and contraction by a variety of techniques, e.g., by applying the cellular PVC siding with heavier than normal nailing (as is the common practice for installing cellular PVC trimboard). This, however, has not been effective. Rather, what is needed is a process for forming cellular PVC siding, wherein the process itself accommodates the fact that cellular PVC siding expands and contracts when exposed to certain temperatures.